Hostname: page-component-5b777bbd6c-sbgtn Total loading time: 0 Render date: 2025-06-18T11:03:21.378Z Has data issue: false hasContentIssue false
  • English
  • Français
Accepted manuscript

Unravelling the role of merger histories in the population of In situ stars: linking IllustrisTNG cosmological simulation to H3 survey

Published online by Cambridge University Press:  04 June 2025

Razieh Emami ,
Lars Hernquist ,
Randall Smith ,
James F. Steiner ,
Grant Tremblay ,
Douglas Finkbeiner ,
Mark Vogelsberger ,
Josh Grindlay ,
Federico Marinacci  and
Kung-Yi Su
...Show all authors
Razieh Emami*
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Lars Hernquist
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Randall Smith
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
James F. Steiner
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Grant Tremblay
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Douglas Finkbeiner
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Mark Vogelsberger
Affiliation:
Department of Physics, Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
Josh Grindlay
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Federico Marinacci
Affiliation:
Department of Physics & Astronomy “Augusto Righi”, University of Bologna, via Gobetti 93/2, 40129 Bologna, Italy INAF, Astrophysics and Space Science Observatory Bologna, Via P. Gobetti 93/3, I-40129 Bologna, Italy
Kung-Yi Su
Affiliation:
Black Hole Initiative at Harvard University, 20 Garden Street, Cambridge, MA 02138, USA
Cecilia Garraffo
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Yuan-Sen Ting
Affiliation:
Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University, Columbus, OH 43210, USA Department of Astronomy, The Ohio State University, Columbus, USA Research School of Astronomy & Astrophysics, Australian National University, Cotter Rd., Weston, ACT 2611, Australia Research School of Computer Science, Australian National University, Acton ACT 2601, Australia
Phillip A. Cargile
Affiliation:
Center for Astrophysics | Harvard & Smithsonian, 60 Garden Street, Cambridge, MA 02138, USA
Rebecca L. Davies
Affiliation:
Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria, Australia ARC Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), Australia
Chloë E. Benton
Affiliation:
Department for Astrophysical and Planetary Science, University of Colorado, Boulder, CO 80309, USA
Yijia Li
Affiliation:
Department of Astronomy & Astrophysics, The Pennsylvania State University, University Park, PA 16802, USA Institute for Gravitation and the Cosmos, The Pennsylvania State University, University Park, PA 16802, USA
Letizia Bugiani
Affiliation:
Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna, Italy
Amir H. Khoram
Affiliation:
Department of Physics & Astronomy “Augusto Righi”, University of Bologna, via Gobetti 93/2, 40129 Bologna, Italy INAF, Astrophysics and Space Science Observatory Bologna, Via P. Gobetti 93/3, I-40129 Bologna, Italy
Sownak Bose
Affiliation:
Institute for Computational Cosmology, Department of Physics, Durham University, South Road, Durham DH1 3LE, UK
*
Corresponding author: Razieh Emami razieh.emami−meibody@cfa.harvard.edu
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We undertake a comprehensive investigation into the distribution of in situ stars within Milky Way-like galaxies, leveraging TNG50 simulations and comparing their predictions with data from the H3 survey. Our analysis reveals that 28% of galaxies demonstrate reasonable agreement with H3, while only 12% exhibit excellent alignment in their profiles, regardless of the specific spatial cut employed to define in situ stars. To uncover the underlying factors contributing to deviations between TNG50 and H3 distributions, we scrutinize correlation coefficients among internal drivers(e.g., virial radius, star formation rate [SFR]) and merger-related parameters (such as the effective mass-ratio, mean distance, average redshift, total number of mergers, average spin-ratio and maximum spin alignment between merging galaxies). Notably, we identify significant correlations between deviations from observational data and key parameters such as the median slope of virial radius, mean SFR values, and the rate of SFR change across different redshift scans. Furthermore, positive correlations emerge between deviations from observational data and parameters related to galaxy mergers. We validate these correlations using the Random Forest Regression method. Our findings underscore the invaluable insights provided by the H3 survey in unravelling the cosmic history of galaxies akin to the Milky Way, thereby advancing our understanding of galactic evolution and shedding light on the formation and evolution of Milky Way-like galaxies in cosmological simulations.

Keywords

Milky Way GalaxyH3 surveyStellar distribution
Type
Research Article
Information
Publications of the Astronomical Society of Australia , Accepted manuscript , pp. 1 - 22
Creative Commons
Creative Common License - CCCreative Common License - BY
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (https://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution and reproduction, provided the original article is properly cited.
Copyright
© The Author(s), 2025. Published by Cambridge University Press on behalf of Astronomical Society of Australia